Strength of Chain and Ropes. 397 The Strength of Chain.—Both sides of the link resist tension, so taking f = 4 tons safe : but r = - .'. W = 6-28 2 -------------- 4 x 4 = 25*12 rz 1 tons safe load. Sir Jno. Anderson deduces a simple rule from the above : (dia. in eighths)2 10 "Safe load in tons. Thus an inch chain bears------= 6*4 tons. , i o _ Strength of Ropes.—For white hemp ft — \ ton safe. But as all ropes are measured by their circumference, and area = —~ Strength of hemp rope = £ x ~~ == "°4 circ'2 (tons)- Wire rope has its members stated by their W.G. Referring to page 276, the total area may be reckoned: then let/t= n| tons safe for ir6n or steel. Strength of Pipes and Cylinders, pressed internally. Imagine a hemispherical vessel A, Fig. 351, hung by a string, and pressed internally; then, as the vessel moves neither to right or left, it follows that the total pressure on the curved surface in direction F is equal to that upon the flat surface. The flat surface is called the * projected area' of the curved surface.